1. Field of the Invention
This invention relates to a rotatable brush for use with dental handpieces. The brush is useful for finishing and polishing a variety of dental structures such as tooth surfaces, direct restorations and indirect restorations.
2. Description of the Related Art
A variety of dental devices for finishing and polishing dental structures are known in the art. Many of these devices are adapted to be connected to a dental handpiece having a rotary drive. If the device is used within the oral cavity of a patient, a releasable connection between the handpiece and the device enables the practitioner to detach the device for disposal or for disinfection before use with a subsequent patient.
Certain types of dental finishing and polishing devices are made of a mixture of a base material such as synthetic resin and an abrasive material such as particles of alumina or zirconia. The synthetic resin is often made of a flexible material that enables the device to bend and deform during use in order to facilitate contact with irregular dental structures as the device is rotating. A wide variety of shapes of such devices are available, including disk shapes, cup shapes, flame shapes and cones or xe2x80x9cpointsxe2x80x9d.
For example, cup-shaped dental polishers are often considered as best suited for polishing occlusal surfaces of teeth, because the cusps of the teeth can be received within the recess of the cup. On the other hand, dental polishers having a cone-shaped configuration or flame-shaped configuration are often considered best suited for polishing fissures and interproximal surfaces of teeth, since the tip of the cone is better adapted to reach within narrow recesses. Disk-shaped polishers are often thought to best treat the front or labial surfaces of teeth, because the disk is better adapted to contact a larger area of a relatively flat surface when the device is rotating.
Other types of finishing and polishing devices used with dental hand pieces are made of a plurality of bristles that are connected to a central hub. In some instances, the bristles together present a generally cup-shaped configuration with a central recess and with free ends of the bristles being generally aligned in a common plane. In other instances, the bristles have different lengths and are arranged so that the bristles together present an overall pointed or flame-shaped configuration, with the longer bristles being located near the central, rotational axis of the hub. The bristles are made separately and connected together by clasping the bristles within a recess of a metal hub.
Finishing and polishing dental structures are considered to be important tasks for the practitioner, because smooth surfaces in the oral cavity are less likely to retain plaque over a period of time. Moreover, once the plaque has accumulated, it is somewhat easier to remove plaque from a smooth surface in the oral cavity in comparison to a surface that is rough. Consequently, the practitioner will normally take steps to help ensure that any newly-placed restoration is smooth and free of bumps, pits and the like.
In addition, a restoration with a smooth exterior surface is more comfortable when brought into contact with the tongue, lips or other tissue in the oral cavity. Furthermore, a restoration having a smooth surface is often considered more aesthetically pleasing, because the smooth surface reflects light to a greater extent than a surface that is not as smooth. A smooth surface of a dental restoration reflects light in a manner similar to the reflection of light from adjacent natural tooth enamel, and consequently is less noticeable and tends to blend in with the surfaces of adjacent teeth.
While the dental devices described above are in widespread use today, there is a continuing need to improve the state of the art so that finishing and polishing of dental structures are facilitated and results of the procedure are enhanced. Preferably, any such improvements would also increase the practitioner""s efficiency and would not unduly add to the overall cost of the dental treatment.
The present invention is directed toward an improved dental handpiece brush that is made with a plurality of bristles. When the brush is not in use, the bristles are oriented in a generally parallel array. However, during rotation of the brush, the outer ends of the bristles converge and form an overall tapered configuration with a narrowed outer tip when the bristles come into contact with dental structure. The tapered configuration of the bristles is particularly useful for finishing and polishing recesses in dental structure, such as the interproximal areas between adjacent teeth.
Preferably, the bristles are integrally molded to a hub as a unitary body. The stiffness of each bristle is selected so that each bristle is relatively flexible. Preferably, the stiffness of the bristles enables the bristles to converge at relatively slow rotational speeds and flare outwardly at relatively high rotational speeds and/or when increased pressure is applied so that relatively flat tooth structure, when encountered, can be quickly finished or polished.
The dental brush of the present invention conforms well to a variety of anatomical surfaces of the teeth, including cusps and grooves of occlusal surfaces, recesses defined by interproximal surfaces and labial surfaces that are relatively flat. As such, the practitioner need not use more than one type of brush during a dental finishing and polishing procedure. The independent bristles of the brush also easily bend during contact with gingival tissue so that the likelihood of undue tissue abrasion or damage is avoided.
In more detail, the present invention in one aspect is directed toward a brush for a dental handpiece. The brush includes a hub and a plurality of bristles connected to the hub. Each of the bristles has a longitudinal axis that normally extends along a path parallel to a reference axis. Each of the bristles has a free outer end. The outer ends converge toward each other and together present an overall tapered configuration when the hub is rotated in an arc at a certain speed about the reference axis and the bristles are in contact with dental structure. At least some of the bristles comprise an elastomeric material and a number of abrasive particles distributed throughout the elastomeric material.
The invention is also directed in another aspect toward an integrally molded brush that comprises a hub and a plurality of bristles connected to the hub. Each of the bristles has a longitudinal axis that normally extends along a path parallel to a reference axis, wherein the bristles are integrally molded with the hub, and wherein at least some of the bristles have a stiffness in the range of about 0.015 lb/in. to about 0.4 lb/in.
Another aspect of the present invention is directed toward a method of treating dental structure. The method includes the act of providing a plurality of bristles that are normally oriented when quiescent along respective paths generally parallel to a certain reference axis. The method additionally includes the act of applying the free end of the bristles to the dental structure. The method also includes the act of rotating the bristles in an arc about the reference axis at a speed sufficient to converge a free end of the bristles toward each other to present an overall tapered configuration while the bristles are rotating and in contact with the dental structure.
These and other aspects of the invention are described in more detail in the text that follows and are illustrated in the accompanying drawings.